1. Field of the Invention
The present invention relates to a device and method for communicating a message in a CDMA (Code Division Multiple Access) communication system, and more particularly, to device and method for multiplexing a message on a physical channel.
2. Description of the Related Art
CDMA mobile communication systems have developed from the IS-955 standard focusing only on a voice service to the next generation CDMA (hereinafter referred to as CDMA 2000) which provides a high-speed data transmission capability for establishing various services including high quality voice, moving pictures, and internet browsing. An IS-95 CDMA communication system operates at a maximum data transmission rate of 9.6 kbps or 14.4 kbps since it is directed to provide a voice service whereas the CDMA 2000 operates at a much higher maximum data transmission rate of 2 Mbps. Therefore, the CDMA 2000 can transmit data 256 times faster than the IS-95 standard.
Furthermore, the two standards may be further differentiated whereby a base station assigns a physical channel to a terminal for a short time when necessary in a CDMA communication system based on the CDMA 2000 standard. To similarly assign a physical channel for a short time for a communication system based on the IS-95 standard, a complex modification needs to be made to an existing IS-95 multiplex option, in which a multiplex configuration depends on the number of connected physical channels. Sixteen (16) bits are required to implement the IS-95 multiplexing option. However, it should be noted that it is difficult to apply the multiplex option to a message as short as 5 ms in duration used for rapid assignment of a physical channel.
In view of the above, it is apparent that to implement the IS-95 multiplexing option, a complex table is required to emulate both support of multiple transmission rates and concurrently connect a plurality of physical channels to provide various services as is done in a communication system based on the CDMA 2000 standard. Consequently, there exists a need for a new multiplex configuration that is superior to the inflexible and complex structures of the existing IS-95 multiplex option.
An object of the present invention is to provide a device and method for constructing a multiplex configuration, in which physical channels are rapidly connected to increase the use efficiency of radio resources in a mobile communication system.
Another object of the present invention is to provide a multiplexing device and method which reflect characteristics of various physical channels.
To achieve the above objects, a multiplexing device and method is provided in a mobile communication system, in which logical channel frames are separated from a received physical channel frame, multiplex units are separated from a logical channel frame, and each multiplex unit is sent to its destination. More precisely, a logical channel multiplexing is performed by receiving a physical channel frame and separating a logical channel frame from the received physical channel frame by analyzing the physical channel frame. Then, a service multiplexing is performed by separating multiplex units from each logical channel frame whose type is defined depending on the type of physical channel containing the logical channel frame and transmitting information of each extracted multiplex unit to a destination.
In accordance with the present invention, multiplexing is implemented in two stages to allow a logical channel to be shared and the type of multiplex unit is defined and the defined multiple unit type is determined depending on the physical channel type, so that the same kind of physical channels employ the same type of multiplex units.